If you save a workbook named Book.xlt, and then put it in a startup folder location, that workbook is the default workbook when you start Excel or open a new workbook. When you load the following types of files from a startup folder, the files have the important characteristics that are described in the following list. You can also use startup folders to load workbooks. You typically use startup folders to load Excel templates and add-ins.
The At startup, open all files in box is under General. To find the At startup, open all files in box in Excel 2007, click Microsoft Office Button, click Excel Options, and then click Advanced. To find the At startup, open all files in box in Excel 2003, click Options on the Tools menu, and then click the General tab.